As is known, the purpose of the follower device in all gyrocompasses is to align an associated indication card, as well as the means (if any) for the transmission of the heading information to a remote load, with the position of the gyrosphere oriented by the gyroscopic effect of the rotating mass contained therein. In compasses with a gyrosphere mechanically suspended from a shaft, the follower has the further purpose of maintaining the cardanic suspension or gimbal mounted oriented in a direction strictly corresponding to that of the gyroscope spin axis, in order to prevent the transmission to the gyrosphere of disturbances caused by the movements of the vehicle on which the gyrocompass is installed. For this second purpose, the follower device of a gyrocompass with mechanical suspension must act with high speed and precision so that the phase difference between the gyrosphere and the cardanic suspension will always be at a minimum, even under the most severe dynamic conditions. Consequently, one must use a motor/reducer group with high acceleration and speed performances to actuate the compass shaft, and a high-resolution sensing for detecting the phase shifts between the gyrosphere and the cardanic suspension. For a correct operation, it is generally deemed that the follower system must be able to develop high accelerations with speeds up to 40.degree./sec.
These features, however, are not compatible with the requirements, particularly as concerns speed, of the system for the transmission of the positional data of the master compass to associated repeaters, a system which must operate with maximum speeds of about 10.degree./sec. Therefore, one accepts compromise solutions which are not completely satisfactory.